Expression of the Grape VaSTS19 Gene in Arabidopsis Improves Resistance to Powdery Mildew and Botrytis cinerea but Increases Susceptibility to Pseudomonas syringe pv Tomato DC3000.

Stilbene synthase (STS) is a key enzyme that catalyzes the biosynthesis of resveratrol compounds and plays an important role in disease resistance. The molecular pathways linking with pathogen responses and their regulation are not known. We isolated an gene, , from a Chinese wild grape, Rupr. cv. "Tonghua-3", and transferred this gene to . We then generated -expressing lines and evaluated the functions of in various pathogen stresses, including powdery mildew, and pv. tomato DC3000 (DC3000). enhanced resistance to powdery mildew and , but increased susceptibility to DC3000. Aniline blue staining revealed that transgenic lines accumulated more callose compared to nontransgenic control plants, and showed smaller stomatal apertures when exposed to pathogen-associated molecular patterns (flagellin fragment (flg22) or lipopolysaccharides (LPS)). Analysis of the expression of several disease-related genes suggested that expression enhanced defense responses though salicylic acid (SA) and/or jasmonic acid (JA) signaling pathways. These findings provide a deeper insight into the function of genes in defense against pathogens, and a better understanding of the regulatory cross talk between SA and JA pathways.